This invention relates to coated articles and coating processes, and more particularly, to a process for improving the adhesion of vinyl resin materials to substrates by the addition of chemical agents to the vinyl resins and to the vinyl resin materials prepared thereby.
The vinyl resins are polymers prepared by polymerization or copolymerization of vinyl monomers including vinyl chloride, vinyl acetate, vinylidene chloride, methyl acrylate, methyl methacrylate and numerous other monomers characterized by the presence of a carbon double bond in the monomer molecule, which opens during polymerization to make possible the carbon chain of the polymer.
Among the applications of vinyl resins which depend upon the ability of the resin to adhere to a substrate are those in which a coating or layer of the vinyl resin and particularly a protective coating is applied to the substrate. When vinyl resins are applied to a substrate, it is generally the practice to first apply a prime coat to the substrate or to incorporate in the vinyl resin a specialized vinyl monomer containing groups, such as carboxyl or hydroxyl, to promote adhesion of the vinyl resin to the substrate. These methods are uneconomical in that they either require the application of multiple coatings, or they require the incorporation of large amounts of the expensive specialized vinyl copolymers, or both.
In another prior art method disclosed in U.S. Pat. No. 3,285,798 adhesive coating agents are provided for anchoring or bonding vinyl resins to textile fabrics. In U.S. Pat. No. 3,285,798 an adhesive comprising an aqueous dispersion of a vinyl resin and an aziridine compound having at least two aziridinyl groups is applied to a textile material and cured prior to laminating the textile material with a vinyl resin. This patented method provides an adhesive composition suitable for laminating a textile to a vinyl resin substrate, in which the adhesive composition is merely an anchoring coating layer applied to hold the elements or layers of the laminated article together. Furthermore, the adhesive composition of U.S. Pat. No. 3,285,798 is applied in the form of an aqueous emulsion. This provides conditions wherein the aziridine can react with the water and thereby consume aziridinyl reactive groups, a factor which not only affects adhesive properties, but which also has an adverse effect upon stability of the aziridine material. The adhesion of a coating material prepared by applying a vinyl resin to which has been added an aqueous dispersion of an aziridine having at least two aziridinyl groups per molecule, is at most poor.